As communication techniques develop rapidly and users desire more functions, a mobile communication terminal (hereinafter, a mobile terminal) provides not only voice information but also text information (such as a stock data, weather, and real time news) and multimedia services multimedia services (such as games and videos.)
However, in order to provide the above services, the number of components and circuits mounted in the mobile terminal has increased, and thereby increasing the time and cost to test for errors of the components and the circuits. To address the problem of testing an increased number of components and circuits, the Joint Test Action Group (JTAG) has developed a boundary-scan testing standard that has been widely adopted. The standard has been published by the IEEE as IEEE Std. 1149.1, and is incorporated herein by reference.
Boundary testing defines a bus structure for testing internal components and circuits. Generally, an exclusive emulator for debugging and testing hardware is provided for testing component and circuit malfunctions. Presently, a JTAG type emulator is being used for this purpose. The JTAG type emulator is an emulator for debugging hardware by mounting standardized logic and test pins for testing a large-scale integrated circuit (LSI) such as a complex programmable logic device (CPLD).
The JTAG type emulator interface requires an additional device such as a flexible printed circuit board (FPCB), and basically the emulator interface comprises five test signals: a test reset (TRST), test data out (TDO), a test clock (TCK), a test mode select (TMS), and a test data in (TDI). The test signals are directly connected to an FPCB, which further connect to components or circuits. A mobile station mode (MSM) controller tests for hardware or connection states.
However, to test circuits and components using the conventional JTAG emulator, a separate space for a JTAG interface is required, but space is a limiting factor in mobile terminal design. Also, the physical configuration for a JTAG interface is different for each mobile terminal design with little standardization. Accordingly, each mobile terminal has to be provided with an additional device for the JTAG interface such as an FPCB.